Burham v-14a-t leaking from tankless coil

Greetings,

I recently inherited my mother's house which is equipped with a v14a-t boiler that has developed a leak from the decommissioned tankless coil... it's a slow leak that only drips when the boiler reaches max temp/pressure.

My google-fu led me to this sight where I was able to find the parts #'s for the gasket and tapped cover plate... the only problem is the plate is on backorder... and further reading leads me to believe that even if I did have the parts there's a good chance I won't get the bolts out without breaking them.

Other internet research led me to a possible stop gap solution in boiler sealant/weld. Does this seem like a feasible solution to this problem?

I realize this boiler is 30yo but would like to get it through the worst of this winter...

Thanks in advance...